//重写alert方法
function alert(str) {   
    var msgw,msgh,bordercolor;   
    msgw=250;//提示窗口的宽度   
    msgh=150;//提示窗口的高度   
    titleheight=25 //提示窗口标题高度   
    bordercolor="#0055e6";//提示窗口的边框颜色   
    titlecolor="#99CCFF";//提示窗口的标题颜色   
    var sWidth,sHeight;   
    //获取当前窗口尺寸   
    sWidth = document.body.offsetWidth;   
    sHeight = document.body.offsetHeight;   
  //背景div   
    var bgObj=document.createElement("div");   
    bgObj.setAttribute('id','alertbgDiv');   
    bgObj.style.position="absolute";   
    bgObj.style.top="0";   
    bgObj.style.background="white";//"#E8E8E8";   
    bgObj.style.filter="progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75";   
    bgObj.style.opacity="0.6";   
    bgObj.style.left="0";   
    bgObj.style.width = sWidth + "px";   
    bgObj.style.height = sHeight + "px";   
    bgObj.style.zIndex = "10000";   
    document.body.appendChild(bgObj);   
    //创建提示窗口的div   
    var msgObj = document.createElement("div")   
    msgObj.setAttribute("id","alertmsgDiv");   
    msgObj.setAttribute("align","center");   
    msgObj.style.background="#ece9d8";   
    msgObj.style.border="1px solid " + bordercolor;   
    msgObj.style.position = "absolute";   
    msgObj.style.left = "50%";   
    msgObj.style.font="12px/1.6em Verdana, Geneva, Arial, Helvetica, sans-serif";   
    //窗口距离左侧和顶端的距离    
    msgObj.style.marginLeft = "-150px";   
    //窗口被卷去的高+（屏幕可用工作区高/2）-150   
    msgObj.style.top = document.body.scrollTop+(window.screen.availHeight/2)-150 +"px";   
    msgObj.style.width = msgw + "px";   
    msgObj.style.height = msgh + "px";   
    msgObj.style.textAlign = "center";   
    msgObj.style.lineHeight ="25px";   
    msgObj.style.zIndex = "10001";   
    document.body.appendChild(msgObj);   
    //提示信息标题   
    var title=document.createElement("h4");   
    title.setAttribute("id","alertmsgTitle");   
    title.setAttribute("align","left");   
    title.style.margin="0";   
    title.style.padding="3px";   
    title.style.background = bordercolor;   
    title.style.filter="progid:DXImageTransform.Microsoft.Alpha(startX=20, startY=20, finishX=100, finishY=100,style=1,opacity=75,finishOpacity=100);";   
    title.style.opacity="0.75";   
    title.style.border="1px solid " + bordercolor;   
    title.style.height="18px";   
    title.style.font="12px Verdana, Geneva, Arial, Helvetica, sans-serif";   
    title.style.color="white";   
    title.innerHTML='提示信息';   
    document.getElementById("alertmsgDiv").appendChild(title);   
    //提示信息   
    var txt = document.createElement("p");   
    txt.setAttribute("id","msgTxt");   
    txt.style.margin="16px 0";   
    txt.innerHTML = str+"<p>窗口将在3秒钟后关闭，<a href='javascript:closewin()'>立刻关闭</a></p>";	
    document.getElementById("alertmsgDiv").appendChild(txt);   
//确定button
//	var btn = document.createElement("button");
//	btn.value="确   定";
//	btn.setAttribute('id','btn1');
//	btn.onclick=function(){
//		bgObj.style.display = "none";
//		msgObj.style.display = "none";
//		title.style.display = "none";
//		
//	}
//	document.getElementById("alertmsgDiv").appendChild(btn);

	
    //设置关闭时间   
  window.setTimeout("closewin()",3000);   
}   
function closewin() {   
    document.body.removeChild(document.getElementById("alertbgDiv"));   
    document.getElementById("alertmsgDiv").removeChild(document.getElementById("alertmsgTitle"));   
    document.body.removeChild(document.getElementById("alertmsgDiv"));   
} 